A medical instrument for driving a short headed nail into bone material is known from DE 195 27 529 A1. The propelling device described therein is designed as a transmitting piston which is biased by a return spring, and translationally driven by a drive piston. Said drive piston is moved pneumatically in a drive pipe until it abuts against the transmitting piston. The cylindrical, elongated head of the nail is inserted into a guide hole formed in the front end of the device, and pushed into the device until the head abuts against a pin formed at the transmitting piston. The nail is translatorily forced into the bone material by the impact applied upon the transmitting piston by the drive piston.
Devices for driving in a Kirschner wire are used in surgery, in particular for the treatment of bone fractures. The Kirschner wire, which is an elongated wire pin made of metal, for example, may easily and rapidly be driven into the bone portions without causing significant injury to the adjacent soft tissue
Such devices are known, for example, from EP 0 597 547 A and DE 27 35 563 A, according to both of which the strokes of the impacting member are transmitted to the wire pin via a receiving sleeve and a clamping device. In the device described in EP 0 597 547, the wire pin is inserted into the device from the rear end thereof, and applied with impact pulses in the form of vibrations which are transmitted via an eccentric clamping device so that the wire is driven to perform an oscillating motion that results in a translatory forward motion thereof. According to DE 27 35 563, the wire is inserted into the front end of the device and clampingly fixed therein. Similar to the operation of a percussion drill, the wire is periodically applied with impact pulses so that it successively advances together with the receiving sleeve, with the other portions of the device being subsequently taken along. The two above described prior art devices must be arranged as close to the bone material as possible so that the wire pin will perform a smooth translatory motion, i.e., the pin does not buckle. To still make sure that a sufficient length of wire material is driven into the bone material, the respective clamping device is designed as a silent ratchet which allows the wire pin to move out of the device, but prevents it from moving back into the device. Thus, the device may contain a sufficient supply of wire material which is successively supplied to be driven into the bone material. Because of their rather complex clamping and gripping devices, said prior art devices are expensive to manufacture. Further, they have a comparatively high energy consumption, which results from the fact that the impacts must be strong enough to move the entire clamping device together with the wire, and that the device must be relatively robust to withstand the extensive mechanical stresses and loads to which it is subjected. Moreover, the impact which may be transmitted to the wire pin itself is rather small.